One

Metallica began work on "One" in November 1987, when James Hetfield and Lars Ulrich wrote the song for the band's fourth album, ...And Justice for All. The sessions started with Mike Clink as producer, but the arrangement did not work out, so the band brought in Flemming Rasmussen, who produced the track alongside the group. Hetfield later explained that the opening chord change came from an idea prompted by the Venom song "Buried Alive", and that the kick drum machine-gun part near the end was not written with the war lyrics in mind. It just came out that way.

The song follows a World War I soldier severely wounded by a land mine. Blind, deaf, and unable to speak or move, he begs God to take his life. The opening twenty seconds carry sound effects of battle, including an artillery barrage and a helicopter, before Hetfield's clean-toned guitar intro gives way to the full band. Released in 1988 as the third and final single from the album, it peaked at No. 35 on the Billboard Hot 100 and reached number one in Finland.

A music video followed, the first the band ever made. Shot in black and white by director Michael Salomon, it debuted on MTV in January 1989 and intercut performance footage with scenes from the 1971 anti-war film Johnny Got His Gun. Because royalty fees were routinely required to keep showing the video, Metallica bought the rights to the film. The song went on to win the first Grammy Award ever given for Best Metal Performance in 1990.